System and method for producing single crystal

Abstract

A system and method for producing a single crystal can prevent calculation and setting mistakes and provide an adequate correction amount in the next batch. A single crystal manufacturing system includes a pulling-up apparatus that calculates a diameter measurement value of a single crystal during a pulling-up process, calculates a first diameter of the single crystal by correcting the diameter measurement value using a diameter correction coefficient, and controls crystal pulling-up conditions based on the first diameter. A diameter measuring apparatus measures a diameter of the single crystal pulled up by the pulling-up apparatus to calculate a second diameter of the single crystal. A database server acquires the first diameter and the second diameter. The database server calculates a correction amount of the diameter correction coefficient from the first and second diameters obtained at diameter measurement positions which coincide with each other under room temperature.

What is claimed: 
     
         1 . A single crystal manufacturing system comprising:
 a single crystal pulling-up apparatus comprising a chamber, a heater, a crucible, a pulling-up mechanism for a crystal, a camera, and a rotating mechanism that rotates the crucible while being heated in the chamber, the single crystal pulling-up apparatus calculates a diameter measurement value of a growing single crystal during a pulling-up process of the growing single crystal according to a CZ method, calculates a first diameter of the growing single crystal by correcting the diameter measurement value using a diameter correction coefficient, and controls a diameter of the growing single crystal based on the first diameter;   a diameter measuring apparatus that measures, under room temperature, a diameter of a previous single crystal pulled up by the single crystal pulling-up apparatus to calculate a second diameter; and   a database server that acquires the first diameter and the second diameter from the single crystal pulling-up apparatus and the diameter measuring apparatus, respectively, and manages them, wherein   the database server calculates a correction amount of the diameter correction coefficient from the first and second diameters obtained at diameter measurement positions which coincide with each other under room temperature and corrects the diameter correction coefficient using the calculated correction amount,   the database server corrects the diameter measurement position of the growing single crystal in a longitudinal direction due to thermal expansion to coincide with a diameter measurement position of the previous single crystal at room temperature;   the database server transmits the calculated correction amount to the pulling-up apparatus; and   the pulling-up apparatus updates the diameter correction coefficient to grow a single crystal.   
     
     
         2 . The single crystal manufacturing system according to  claim 1 , wherein
 the crystal pulling-up apparatus has a camera photographing a boundary between the growing single crystal and a melt during the single crystal pulling-up process and calculates the diameter measurement value of the growing single crystal from a photographed image of the camera.   
     
     
         3 . The single crystal manufacturing system according to  claim 1 , wherein
 the database server sets the diameter correction coefficient after being corrected in the single crystal pulling-up apparatus, and   the single crystal pulling-up apparatus corrects a diameter measurement value of a single crystal in the next batch using the corrected diameter correction coefficient.   
     
     
         4 . The single crystal manufacturing system according to  claim 1 , wherein
 the correction amount of the diameter correction coefficient is a value obtained by multiplying the difference or ratio between the first and second diameters obtained at diameter measurement positions which coincide with each other under room temperature by a gain, and the gain is more than 0 and equal to or less than 1.   
     
     
         5 . The single crystal manufacturing system according to  claim 1 , wherein
 the single crystal pulling-up apparatus and the diameter measuring apparatus are connected to the database server over a communication network,   the single crystal pulling-up apparatus transmits the first diameter of the growing single crystal, a diameter measurement position at which the first diameter is measured, and an ingot ID of the growing single crystal to the database server,   the diameter measuring apparatus transmits the second diameter of the previous single crystal, a diameter measurement position at which the second diameter is measured, and an ingot ID of the single crystal to the database server,   the database server registers the first diameter from the single crystal pulling-up apparatus and the second diameter from the diameter measuring apparatus in association with each other.   
     
     
         6 . The single crystal manufacturing system according to  claim 1 , wherein
 the database server corrects the diameter measurement position at which the single crystal pulling-up apparatus performs measurement using a crystal length correction coefficient considering thermal expansion of the growing single crystal, and calculates a correction amount of the diameter correction coefficient from the first and second diameters measured at diameter measurement positions which coincide with each other using the corrected diameter measurement position.   
     
     
         7 . A single crystal manufacturing method comprising:
 heating a polysilicon raw material in a crucible to generate a silicon melt;   pulling up a seed crystal while being rotated together with the crucible which grows a single crystal;   photographing a liquid surface of the silicon melt and the growing single crystal and creating an image;   calculating a diameter measurement value of the growing single crystal from the image;   calculating a first diameter of the growing single crystal by correcting the diameter measurement value using a diameter correction coefficient, and controlling a crystal diameter based on the first diameter;   a diameter measurement step of measuring, under room temperature, a diameter of a single crystal previously pulled up to calculate a second diameter; and   a management step of acquiring the first and second diameters and managing them, wherein   the managing step includes a diameter correction coefficient correction step of calculating a correction amount of the diameter correction coefficient from the first and second diameters obtained at diameter measurement positions which coincide with each other under room temperature, comprising correcting the diameter measurement position of the growing single crystal in the longitudinal direction due to thermal expansion to coincide with the diameter measurement position of the previous single crystal at room temperature, and correcting the diameter correction coefficient using the calculated correction amount; and   controlling the rate of pulling up the growing single crystal based on a crystal diameter value converted into a diameter value under room temperature.   
     
     
         8 . The single crystal manufacturing method according to  claim 7 , wherein the managing step corrects the diameter measurement position at which the single crystal pulling-up apparatus performs measurement using a crystal length correction coefficient considering thermal expansion of the growing single crystal, and calculates a correction amount of the diameter correction coefficient from the first and second diameters measured at diameter measurement positions which coincide with each other using the corrected diameter measurement position.